Often, hydrocarbon and gas streams are treated to remove sulfur-containing compounds, such as sulfides and mercaptans. Generally, such compounds are removed because of their malodorous scent.
Mercaptans can be designated R—S—H where R is often a light hydrocarbon radical such as methyl or ethyl. Typically, mercaptans concentrate in hydrocarbon liquid streams separated in a process facility. Many processes can be used to remove mercaptans and other sulfur-containing compounds. Often, such processes can use an alkaline stream contacting the hydrocarbon stream in an extractive system.
After extraction, the alkaline stream may be regenerated. The sulfides are typically removed in a sulfide oxidation reactor which also oxidizes the mercaptides to disulfides. The effluent from the sulfide oxidation reactor contains alkali, disulfide oils, and various vapors. The effluent is then separated in a disulfide separator into a lean alkaline stream, a disulfide oil stream, and a vapor stream which includes primarily air and small amounts of water, hydrocarbons, and disulfide oils. Typically, the vapor stream can contain up to about one mole percent disulfide.
There is a need for methods of processing the rich alkali which provide improved removal of the disulfides from the regenerated liquid alkaline stream and the vapor stream.